There are a number of different containers of varying geometric configurations, including cylindrical and box-like containers used for the sale of food products including yogurt. These containers are typically made of disposable material and after having been emptied, are thrown away. Certain attempts have been made to find another useful purpose for the single use containers. The Young patents and Pinkau disclose food containers, which, when empty, serve as an assembly construction kit for children. In such an assembly, a number of containers are provided with interengageable connection parts in order that a structure comprised of a number of the containers can be constructed.
Young et al 5,054,617 and Young et al 4,919,268 are directed to containers which can be later used in conjunction with other similar containers, as a construction kit. The containers disclosed in Young include connection parts comprised of holes, projections and a cruciform; the holes located adjacent but spaced within a peripheral flange. The projections of one container are designed to fit within the holes of an adjacent container in order that two containers are interconnected. In order that the intended structure shown in Young fit snugly together, close tolerances between the holes and projections are required. These close tolerances are important so that the assembled containers stay together when subjected to the abuses of small children. It is not economical to manufacture such containers with precise dimensions, especially since the food within the containers, and not the containers themselves, are the primary product. Therefore, the connection parts fit loosely together resulting in containers that do not stay fitted together, much to the disappointment of small children.
Pinkau et al 4,067,475 discloses a container assembly system using a projection and recess system. Each container utilizes a peripheral bead at the end of a flat edge as the projection component. The container has a base support which contains a slot that opens into a round recess. The bead of one container fits into the recess of another container and is held in place in only one direction since the bead cannot slide out the slot. However, it is impractical to manufacture a bead and recess to close tolerances to ensure a tight fit between the recess and the bead. The forming and cutting dies generally used to manufacture such containers in volume do not retain close tolerances after repeated uses. Therefore, even though the bead will not fit through the slot, the bead can easily slide out of the recess, resulting in containers not fitting snugly together, and susceptible to becoming disconnected upon even casual handling.
Parker et al 3,303,965 describes plastic stackable containers. Each container has a flange with an inner peripheral edge with recesses and ribs at the bottom portion. The container fits within another container by seating of the ribs of the upper container within the inner peripheral edge of the flange of the lower container. The stacking characteristics do not provide for building structures of differing configurations and are designed for utilitarian purposes, not as toys for small children. Importantly, the ribs fit loosely into the inner edge. Therefore, the container system of Parker consists of individual containers loosely stacked. The entire system of Parker cannot be moved intact by picking up only one container.
The above described prior art discloses containers which, when fitted together, are loosely engaging. When the complementary connection parts consist of projections and holes, it is impractical and uneconomical to manufacture the parts to the necessary close tolerances which would result in a tight or snug fit between complementary parts. The resultant containers have loosely engaging connection parts. The containers are easily disconnected and toppled, much to the disappointment of small children. The containers cannot be picked up and moved as a unit without falling apart. Additionally, prior art containers cannot be placed or constructed on their sides without the connection parts disengaging.